Add grey text "Add coupon code" to blank space on Cart page
My clients are getting confused about where to enter the coupon code at times. I suggest adding grey text "Add coupon code here" or just "coupon code" to the white field to the left of the "Apply Coupon" button on the cart page, so it is consistent with the coupon code field on the checkout page. I am losing some customers as they don't go on to the Checkout page without being certain the code can be applied.
Assuming your browser supports placeholder text (almost all do now) you should see “Coupon Code” in the field.